Elephants in the room

David MacKay FRS

Department of Engineering
University of Cambridge

Former Chief Scientific Advisor
Department of Energy and Climate Change

Inconsistency with any cost-optimal pathway

Negative emissions

Successful action requires extremely large negative emissions (in order to make net emissions zero).
No countries are developing negative emissions technologies.
Not all countries would be able to deploy negative emissions.

Diet and farming practices

The strongest levers in the global calculator!

Biomass – carbon accounting in the landscape

Some states are switching to bioenergy, but it has limited technical potential, it fights with food,
and increasing bioenergy farming may well cause net carbon emissions.

Climate change is a commons problem

Paris pretends to have solved the commons problem – but has not employed any of the lessons
of the science of cooperation.
Why will parties "raise their ambition" to the required level?

Population

Beware climate policies that incentivise population growth?

Economic growth

Inconsistency with any cost-optimal pathway

Negative emissions

Diet and farming practices

Biomass – carbon accounting in the landscape

Climate change is a commons problem

Population

Economic growth

Inconsistency with any cost-optimal pathway

Negative emissions

Successful action requires extremely large negative emissions (in order to make net emissions zero).
No countries are developing negative emissions technologies.
Not all countries would be able to deploy negative emissions.

10-20 (or 40) Gt CO2 / year
(85 M barrels per day)

Diet and farming practices

The strongest levers in the global calculator!

The Global Calculator –
globalcalculator.org

Biomass versus reforestation – carbon accounting in the landscape

Some states are switching to bioenergy, but it has limited technical potential, it fights with food,
and increasing bioenergy farming may well cause net carbon emissions.

Source: IPCC

"BEaC"

Climate change is a commons problem

Paris pretends to have solved the commons problem – but has not employed any of the lessons
of the science of cooperation.
Why will parties "raise their ambition" to the required level?